Motor



W. A. SMITH.

MOTOR.

' APPLICATION FILED OCT-16, I916 RENEWED M 1,401,003.

AY 9, 1921. i Patented Dec. 20, 1921.

UNITED STATES PATENT OFFICE.

WILLIAM A. SMITH, OF PHILLIPSBURG, NEW JERSEY, ASSIGNOR TO THE DENVER ROCK DRILL MANUFACTURING COMPANY, OF DENVER, COLORADO, A CORPO- RATION OF DELAWARE.

MOTOR.

Patented Dec. 20, 1921.

Application filed October 16, 1916, Serial No. 125,945. Renewed Mayfl, 1921. Serial No.468,170.

To all whom it ma'y concern:

Be it known that}, WILLIAM A. SMITH, a citizen of the United States, residing at Phillipsburg, in the county of Warren and State of New Jersey, have invented certain new and useful Improvements in Motors, of which the following is a specification.

The present invention relates to motors operated by fluid under pressure, and more particularly is of the valveless type.

It has been proposed in tools of this character to control the admission of motive fluid by necks extending from the piston head proper, and in certain instances these necks have also performed the function of a hammer extension that delivers the blow to the tool, either directly, or through the interposition of a tappet. In one type in which a rear extension or neck has been employed, the neck has constituted solely the motive ,fluid controlling means, and is not only inactive in receivlng pressure from the motive fluid, but actually detracts from the power obtained because of the surface it occupies at its juncture with-the piston head, which surface is thus made idle. In the modern development of this type of tools, moreover, where rapid and relatively heavy blows are given, unless these necks are of material thickness, they are apt to break off, so that their cross sectional area with respec to the piston head must be relatively great.

One of the primary objects of the present invention is to provide a construction of this type, wherein the surface of the piston head occupied by the junction therewith of the neck and thus made inactive, is compensated for by an active surface provided upon the neck, and as a result, a surface equal to the entire cross sectional area of the piston head is secured on the active or striking blow of the hammer.

An embodiment of the invention is illustrated in the accompanying drawings, wherein Figure 1 is a longitudinal sectional view through a tool with the piston in one extreme position, and

Fig. 2 is a similar view with the piston in the opposite extreme position.

Similar reference numerals designate corresponding parts in all the figures of the drawings.

In the embodiment illustrated, a cylinder member is employed, comprising a body 3 having a rear head 4 and a front head 5, to which is connected 2. suitable tool holder or chuck 6, a dolly 7 being illustrated as the tool mounted in the holder or chuck. The cylinder body is provided with a bore 8 which may be termed a head chamber, the rear head being provided with a distinctive chamber 9 of smaller diameter, which may be considered-a neck chamber. The front head 5 is also provided with a bore 10, ,which I have also entitled a neck chamber.

so that the piston can be reversed and either end used as the hammer extension. This materially lengthens the life of the piston.

The neck 12 has a reduced portion 14 contiguous to its juncture with the head 11, and the neck 13 also has a reduced portion 15 also adjacent to the head 11. These two reduced portions 14. and 15 form in effect annular grooves or channels on opposite sides of the piston head. The portions of the necks l2 and 13 directly adjacent to the head 11 are in the form of bosses 14 and 15 which fit the inner ends of the neck chambers 9 and 10 so as to substantially close the same and trap the motive-fluid on opposite sides of the head 11 at the ends of its stroke, so as to produce cushions whenever the head for any reason makes a stroke the extreme length of the head chamber. Motive fluid supplied from any suitable source is conducted by suitable means,not shown,to

a supply port 16, and from this supply port,

oppositely extending channels 17 and 18-lead to annular grooves 19 and 20 formed respectively in the heads 4 and 5 and surrounding the chambers 9 and 10. An exhaust port 21 opens into an intermediate portion of the 'head chamber 8, communicating with an in- When motive fluid is admitted through the port 16, if the piston is in the position shown in Fig. 1, the fluid is cut off from the front end of the head chamber by the front end of the neck 13, but can flow through the channel 17, and oove 14 into the rear end of the head cham er 8 behind the piston 11. The piston head being. behind the exhaust ort 21 and channel 22, the portion of the head chamber 8 in advance of the piston is open to the atmosphere, and consequently the piston will be driven forwardly to strike its blow. In connection with this forward movement, it will be noted that the motive fluid which enters behind the piston head- 11 will also flow through the channel, 23 into the rear end of the neck chamber 9, and consequently against the rear end of said neck. Therefore the rear surface 25 of said neck and the rear surface 26 of the head are both acted on simultaneously, and a pressure surface equal in extent to the entire cross sectional area of the piston head 11 is securedf As the piston advances, the rear end of the rear neck 12 will cut off communication between the channel 17 and the rear end of the head chamber 8, While the front channel 18 will be brou ht into communication with the front end 01 the head chamber 8 in advance of the piston 11 as seen in Fig. 2. The piston head 11 will also cross the groove 22 and.

exhaust port 21, so that now the motive fluid will act against the front end of the piston head 11 and the motive fluid in rear of said head can exhaust freely. It will also be noted that the neck chamber 9 is also opened 7 only against the rear surface 26 of the head 11, but also against the rear surface 25 of the neck 12.

With this construction therefore a heav striking blow can be secured,-and the diameter of the neck 12 which controls the supply of motive fluidto the rear face of the head, may also be relatively great, inasmuch as the surface thus occupled by the neck is compensated for by the surface at the rear end of the neck."

From the foregoing, it is thought that the construction, operation and many advantages of theherein described invention will bea parent to those skilled in the art, without urther description, and it will be understood that variouschanges in the size, shape, proportion. and minor details of construc- .tion may be resorted to without departin from the spirit or sacrificing any of the a vantages of the invention.

Havin thus fully described my invention, what I c aim'as new,-and desire to secure by Letters Patent, is:-

1. In a motor of the character set forth,

the combination with a cylinder member having a head chamber and opposite neck chambers extending therefrom, saidcylinder member hav'in supply ports opening into the neck cham ers, of a piston operating in. the cylinder member and comprising a head in the head chamber and necks respectively operating in the neck chambers, said necks having reduced portions of less cross sectional area than the neck chambers to alternately and intermittently afl'ord communication between the ports and the head chamber on opposite sides of the head, and bosses at the juncture of the head and necks that substantially close the inner ends of the neck chambers whenever the piston makes a stroke of extreme length, thereby forming cushions of trapped motive fluid.

2. In a motor of the character set forth, the combination with a cylinder member having distinctive piston chambers, of a piston operating in the cylinder member and having different portions in the diifer- 'ent" chambers, said portions respectively having pressure surfaces faced in the same direction, and means for directing motive fluid to one. chamber against the surface therein and'exhausting it therefrom, and a channel constituting means of communication-between the rear ortion of said chamber and the front ortlon of the other chamher, said latter 0 amber from the channel rearwardly having a diameter greater than that of the portion of the piston therein, permitting the supply to flow from the first mentioned chamber to said other chamber in rear of the piston, and the exhaust to flowof a piston having a head operating in the head chamber, and a neck operating in the neck chamber, means for supplying motive fluid to the head chamber to operate against said head, means for permitting the exhaust to escape from said head chamber, and a channel between the rear portion of the head chamber and the front portion of the neck chamber, and said neck chamber from the channel rearwardly having an increased diameter that causes 1ts walls to be spaced from the neck of the piston and said chanml and enlarged diameter permitting the entrance of motive fluid to the neck chamber in rear of the neck and its exhaust therefrom by way of the head chamber.

4. In a motor of the character set forth, the combination with a cylinder member having a head chamber and a neck chamher having a reduced portion that communicates with the head chamber, of a piston having a head operating in the head chamber, said neck fitting the reduced portion and being spaced from the walls of the portion in t e rear thereof, means for supplying motive fluid to the-head chamber through the reduced portion of the neck chamber to operate against said head, means for permitting the exhaustto escape from said head chamber,- and a channel between, the rear portion of the head chamber and the front enlarged portion of the neck chamber for permittmg the entrance of motive fluid to the latter and thence to the rear end of the neck and its exhaust therefrom by way of the head chamber, said neck constituting means'for controlling the supply of motive fluid to the head chamber and consequently to the neck chamber. r i

5. In a motor of the character set forth, the combination with a cylinder member having a head chamber and a neck chamber of less diameter extending rearwardly therefrom, of a piston having a head operating in the head chamber and a neck operating in the neck chamber, the front portion of the. walls of the'neck chamber snugly encircling the neck of the piston to revent commumcation between the two c ambersand the rear portion of the encircling walls of the 4 against the rear faces of the head and neck. 7

6. In a motor of the character set forth, the combination with a cylinder member havin a head chamber and a neck chamber 0 less diameter extendingrearwardly therefrom, of a piston having a head operating in the head chamber and a-neck operatin in the neck chamber, the front portion of the walls of the neck chamber snugly encircling the neck of the piston to prevent communication betweenthe two chambers and the rear portion of said neck chamber being enlarged, the encircling walls of said enlarged, portion being spaced from said neck, and means for directing motive fluid to the head chamber and the enlarged portion of the neck chamber to act against the rear faces of the head and neck In testimony whereof, I aflix my signature presence (if tWO WILLIAM} .-AJ SMITH,

' Witn: J

' Wnmn H. Lnonam;

Jim B. Y 

